Reaction products of amine monomers and polymers containing saturated heterocyclic moieties as additives for electroplating baths

ABSTRACT

Reaction products of amines and polymers containing saturated heterocyclic moieties may be used as levelers in metal electroplating baths. The reaction products may plate metal with good surface properties and good physical reliability.

The present application is a divisional application of co-pendingapplication Ser. No. 15/560,228, filed Sep. 21, 2017.

FIELD OF THE INVENTION

The present invention is directed to reaction products of amine monomersand polymers containing saturated heterocyclic moieties as additives forelectroplating baths. More specifically, the present invention isdirected to reaction products of amine monomers and polymers containingsaturated heterocyclic moieties for electroplating baths which may beused as levelers in electroplating baths to provide good throwing power.

BACKGROUND OF THE INVENTION

Methods for electroplating articles with metal coatings generallyinvolve passing a current between two electrodes in a plating solutionwhere one of the electrodes is the article to be plated. A typical acidcopper plating solution includes dissolved copper, usually coppersulfate, an acid electrolyte such as sulfuric acid in an amountsufficient to impart conductivity to the bath, a source of halide, andproprietary additives to improve the uniformity of the plating and thequality of the metal deposit. Such additives include levelers,accelerators and suppressors, among others.

Electrolytic copper plating solutions are used in a variety ofindustrial applications, such as decorative and anticorrosion coatings,as well as in the electronics industry, particularly for the fabricationof printed circuit boards and semiconductors. For circuit boardfabrication, typically, copper is electroplated over selected portionsof the surface of a printed circuit board, into blind vias and trenchesand on the walls of through-holes passing between the surfaces of thecircuit board base material. The exposed surfaces of blind vias,trenches and through-holes, i.e. the walls and the floor, are first madeconductive, such as by electroless metallization, before copper iselectroplated on surfaces of these apertures. Plated through-holesprovide a conductive pathway from one board surface to the other. Viasand trenches provide conductive pathways between circuit board innerlayers. For semiconductor fabrication, copper is electroplated over asurface of a wafer containing a variety of features such as vias,trenches or combinations thereof. The vias and trenches are metallizedto provide conductivity between various layers of the semiconductordevice.

It is well known in certain areas of plating, such as in electroplatingof printed circuit boards (“PCBs”), that the use of levelers in theelectroplating bath can be crucial in achieving a uniform metal depositon a substrate surface. Electroplating a substrate having irregulartopography can pose difficulties. During electroplating a voltage droptypically occurs within apertures in a surface, which can result in anuneven metal deposit between the surface and the apertures.Electroplating irregularities are exacerbated where the voltage drop isrelatively extreme, that is, where the apertures are narrow and tall.Consequently, depositing a metal layer of substantially uniformthickness is frequently a challenging step in the manufacture ofelectronic devices. Leveling agents are often used in copper platingbaths to provide substantially uniform, or level, copper layers inelectronic devices.

The trend of portability combined with increased functionality ofelectronic devices has driven the miniaturization of PCBs. Conventionalmultilayer PCBs with through-hole interconnects are not always apractical solution. Alternative approaches for high densityinterconnects have been developed, such as sequential build uptechnologies, which utilize blind vias. One of the objectives inprocesses that use blind vias is the maximizing of via filling whileminimizing thickness variation in the copper deposit between the viasand the substrate surface. This is particularly challenging when the PCBcontains both through-holes and blind vias.

Leveling agents are used in copper plating baths to level the depositacross the substrate surface and to improve the throwing power of theelectroplating bath. Throwing power is defined as the ratio of thethrough-hole center copper deposit thickness to its thickness at thesurface. Newer PCBs are being manufactured that contain boththrough-holes and blind vias. Current bath additives, in particularcurrent leveling agents, do not always provide level copper depositsbetween the substrate surface and filled through-holes and blind vias.Via fill is characterized by the difference in height between the copperin the filled via and the surface. Accordingly, there remains a need inthe art for leveling agents for use in metal electroplating baths forthe manufacture of PCBs that provide level copper deposits whilebolstering the throwing power of the bath.

SUMMARY OF THE INVENTION

A reaction product of one or more amine monomers and one or morepolymers, where the polymers are composed of a reaction product of twoor more monomers having a formula:

where A is a saturated 5 or 6 membered heterocyclic ring composed of 4or 5 carbon atoms, the carbon atoms of the ring not part of the carbonylmoiety are independently substituted or unsubstituted; Z is a nitrogenatom or an oxygen atom and Z₁ is a carbon atom or an oxygen atom withthe proviso that when Z is oxygen A is a 6 membered ring and Z₁ is acarbon atom, and when Z₁ is oxygen A is a 6 membered ring and Z isnitrogen; and R is a substituent group including hydrogen, linear orbranched alkyl, linear or branched hydroxyalkyl, linear or branchedhaloalkyl, linear or branched aminoalkyl, linear or branched vinylalkylor —CH₂—O—(R′—O)_(d)—CH₂—Y where R′ is a linear or branched(C₂-C₁₀)alkyl, Y is hydroxyl or halogen and d is an integer of 1-10 andn is 0 or 1 with the proviso that when n is 0, Z is an oxygen atom.

A composition including one or more sources of metal ions, anelectrolyte and one or more compounds of a reaction product of one ormore amine monomers and one or more polymers, where the polymers arecomposed of a reaction product of two or more monomers having a formula:

where A is a saturated 5 or 6 membered heterocyclic ring composed of 4or 5 carbon atoms, the carbon atoms of the ring not part of the carbonylmoiety are independently substituted or unsubstituted; Z is a nitrogenatom or an oxygen atom and Z₁ is a carbon atom or an oxygen atom withthe proviso that when Z is oxygen A is a 6 membered ring and Z₁ is acarbon atom, and when Z₁ is oxygen A is a 6 membered ring and Z isnitrogen; and R is a substituent group including hydrogen, linear orbranched alkyl, linear or branched hydroxyalkyl, linear or branchedhaloalkyl, linear or branched aminoalkyl, linear or branched vinylalkylor —CH₂—O—(R′—O)_(d)—CH₂—Y where R′ is a linear or branched(C₂-C₁₀)alkyl, Y is hydroxyl or halogen and d is an integer of 1-10 andn is 0 or 1 with the proviso that when n is 0, Z is an oxygen atom.

A method including: providing a substrate; providing a compositioncomprising one or more sources of metal ions, an electrolyte and one ormore compounds of a reaction product of one or more amine monomers andone or more polymers, wherein the polymers are composed of a reactionproduct of two or more monomers having a formula:

where A is a saturated 5 or 6 membered heterocyclic ring composed of 4or 5 carbon atoms, the carbon atoms of the ring not part of the carbonylmoiety are independently substituted or unsubstituted; Z is a nitrogenatom or an oxygen atom and Z₁ is a carbon atom or an oxygen atom withthe proviso that when Z is oxygen A is a 6 membered ring and Z₁ is acarbon atom, and when Z₁ is oxygen A is a 6 membered ring and Z isnitrogen; and R is a substituent group including hydrogen, linear orbranched alkyl, linear or branched hydroxyalkyl, linear or branchedhaloalkyl, linear or branched aminoalkyl, linear or branched vinylalkylor —CH₂—O—(R′—O)_(d)—CH₂—Y where R′ is a linear or branched(C₂-C₁₀)alkyl, Y is hydroxyl or halogen and d is an integer of 1-10 andn is 0 or 1 with the proviso that when n is 0, Z is an oxygen atom.

The reaction products may be included in metal electroplating baths toprovide metal layers having a substantially level surface across asubstrate, even on substrates having small features and on substrateshaving a variety of feature sizes. The plating methods effectivelydeposit metals on substrates and in blind vias and through-holes suchthat the metal plating compositions have good throwing power.

DETAILED DESCRIPTION OF THE INVENTION

As used throughout this specification the following abbreviations shallhave the following meanings unless the context clearly indicatesotherwise: A=amperes; A/dm²=amperes per square decimeter=ASD; °C.=degrees Centigrade; g=gram; mg=milligrams, L=liter; ppm=parts permillion=mg/L; μm=micron=micrometer; mm=millimeters; cm=centimeters;DI=deionized; mL=milliliter; mol=moles; mmoles=millimoles; Mw=weightaverage molecular weight; and Mn=number average molecular weight. Allnumerical ranges are inclusive and combinable in any order, except whereit is clear that such numerical ranges are constrained to add up to100%.

As used throughout the specification, “feature” refers to the geometrieson a substrate. “Aperture” refers to recessed features includingthrough-holes and blind vias. As used throughout this specification, theterm “plating” refers to metal electroplating. “Deposition” and“plating” are used interchangeably throughout this specification.“Leveler” refers to an organic compound or salt thereof that is capableof providing a substantially level or planar metal layer. The terms“leveler” and “leveling agent” are used interchangeably throughout thisspecification. “Accelerator” refers to an organic additive thatincreases the plating rate of the electroplating bath (may be synonymouswith brightener). “Suppressor” refers to an organic additive thatsuppresses the plating rate of a metal during electroplating. The term“amine monomer” within the scope of the invention is an organic nitrogencompound which includes at least one primary or secondary aminefunctionality and is not a polymer. The term “polymer” refers to acompound of two or more monomers which may be the same or different andincludes dimers. The term “copolymer” refers to a polymer of two or moredissimilar monomers. The term “homopolymer” refers to a polymer of twoor more of the same monomers. The terms “printed circuit boards” and“printed wiring boards” are used interchangeably throughout thisspecification. The term “moiety” means a part of a molecule or polymerthat may include either whole functional groups or parts of functionalgroups as substructures. The terms “moiety” and “group” are usedinterchangeably throughout the specification. The “----” dashed line inchemical structures means an optional double bond. The articles “a” and“an” refer to the singular and the plural.

The compounds are copolymers of reaction products of one or more aminesand one or more polymers, where the polymers may be copolymers orhomopolymers and are composed of a reaction product of two or moremonomers including an imide or anhydride functionality in a saturatedring, such monomers are those having a formula:

where A is a saturated 5 or 6 membered heterocyclic ring composed of 4or 5 carbon atoms, the carbon atoms of the ring not part of the carbonylmoiety are independently substituted or unsubstituted; Z is a nitrogenatom or an oxygen atom and Z₁ is a carbon atom or an oxygen atom withthe proviso that when Z is oxygen A is a 6 membered ring and Z₁ is acarbon atom, and when Z₁ is oxygen A is a 6 membered ring and Z isnitrogen; and R is a substituent group including but not limited tohydrogen, linear or branched alkyl such as (C₁-C₅)alkyl, linear orbranched hydroxyalkyl such as hydroxy(C₁-C₅)alkyl, linear or branchedhaloalkyl such as halo(C₁-C₅)oalkyl where the halogen is chlorine,fluorine, bromine or iodine, linear or branched aminoalkyl such asamino(C₁-C₅)alkyl, linear or branched vinylalkyl such as(C₁-C₅)vinylalkyl, or —CH₂—O—(R′—O)_(d)—CH₂—Y where R′ is a linear orbranched (C₂-C₁₀)alkyl, Y is hydroxyl or halogen where the halogen ischlorine, fluorine, bromine or iodine and d is an integer of 1-10 and nis 0 or 1 with the proviso that when n is 0, Z is an oxygen atom.

Substituent groups on the carbons of the ring include, but are notlimited to linear or branched (C₁-C₅)alkyl, hydroxyl, linear or branchedhydroxy(C₁-C₅)alkyl, linear or branched carboxy(C₁-C₅)alkyl, linear orbranched (C₁-C₅)alkoxy, linear or branched halo(C₁-C₅)alkyl, aryl,linear or branched arylalkyl, and linear or branched, aminoalkyl.

Preferably, the monomers are those which include an imide functionalityin the saturated ring having a formula:

where R, n and Z₁ are as defined above. Preferably, Z₁ is a carbon atomand ring A is a 5 membered ring.

The monomers including the imide or anhydride functionality in thesaturated ring may be reacted together by conventional polymerizationmethods known in the art such as condensation reactions or additionreactions. Preferably, monomers including the imide functionality arereacted with each other and monomers including the anhydridefunctionality are reacted with each other. The polymers formed may becopolymers or homopolymers. Such polymers also include dimers. A numberof the polymers are commercially available such as polysuccimide andbismaleimide.

Preferred polymers include those having the following formulae:

where R₁ and R₂ may be the same or different and R₃, R₄, R₅ and R₆ maybe the same or different and include, hydrogen, linear or branched(C₁-C₅)alkyl, hydroxyl, linear or branched hydroxy(C₁-C₅)alkyl, linearor branched carboxy(C₁-C₅)alkyl, linear or branched (C₁-C₅)alkoxy,linear or branched halo(C₁-C₅)alkyl, aryl, linear or branched arylalkyl,and linear or branched, aminoalkyl and m is an integer of 2 and greater,preferably 2 to 12, more preferably 2 to 8. Preferably, R₁, R₂, R₃, R₄,R₅ and R₆ are independently chosen from hydrogen and (C₁-C₃)alkyl, morepreferably R₁, R₂, R₃, R₄, R₅ and R₆ are hydrogen. Preferably thepolymer has structure (III) and is a polysuccimide.

Dimers may have the following general formulae:

where A, Z, Z₁ and R are as defined above and R″ is R₁₀ or R₁₅ asdefined below.

Preferred dimers include those having the following formulae:

wherein R₁₁-R₁₄, R₁₇-R₂₃ and R₂₅-R₂₆ are independently hydrogen, linearor branched (C₁-C₅)alkyl, hydroxyl, linear or branchedhydroxy(C₁-C₅)alkyl, linear or branched carboxy(C₁-C₅)alkyl, linear orbranched (C₁-C₅)alkoxy, linear or branched halo(C₁-C₅)alkyl, aryl,linear or branched arylalkyl, and linear or branched, aminoalkyl; R₁₅ isa moiety chosen from —CH₂—O—(R′—O)_(d)—CH₂— where R′ and dare as definedabove or a moiety having formula:

where R₂₇ and R₂₈ are independently hydrogen or (C₁-C₃)alkyl, p is aninteger of 1 to 10, and R₁₆ has a moiety of formula (XII).

Amine monomers include organic nitrogen compounds which have at leastone primary or secondary amine functionality which reacts with thepolymer including an imide or anhydride functionality to form a polymerreaction product. Such amines include those having formulae:

where R₂₉ is hydrogen or linear or branched (C₁-C₅)alkyl, r is aninteger of 0 to 8 with the proviso that when r is 0, R′ is joined to thenitrogen atom by a covalent bond. Preferably R₂₉ is hydrogen. Preferablyr is 1-4.

R′ is a nitrogen containing moiety which may be linear or branchednitrogen containing groups, aromatic or non-aromatic heterocyclicgroups. Linear or branched nitrogen containing moieties include, but arenot limited to those having a general formula:

where R₃₀ and R₃₁ are independently hydrogen or linear or branched(C₁-C₅)alkyl and q is an integer of 1-10, preferably from 1 to 4.

Heterocyclic aromatic and non-aromatic nitrogen containing moietiesinclude but are not limited to those derived from heterocyclic nitrogencompounds such as imidazoles, triazoles, tetrazoles, pyrazines,benzimidazoles, benzotriazoles, purines, piperazines, pyridazines,pyrazoles, triazines, tetrazines, pyrimidines, piperidines,benzoxazoles, oxazoles, pyridines, morpholines, pyrrolidines, pyrroles,quinolines, isoquinolines and benzothiazoles. The heterocyclic nitrogenmoieties may have one or more substituent groups joined to the rings.Such substituent groups include, but are not limited to, linear orbranched, substituted or unsubstituted alkyl, hydroxyl, nitro ornitroalkyl, nitroso or nitrosoalkyl, carbonyl, mercapto ormercaptoalkyl, linear or branched hydroxyalkyl, carboxyl, linear orbranched carboxyalkyl, linear or branched alkoxy, substituted orunsubstituted aryl, linear or branched, substituted or unsubstitutedarylalkyl, linear or branched, substituted or unsubstituted aminoalkyl,substituted or unsubstituted sulfonyl, linear or branched, substitutedor unsubstituted amine. Also included are salts of the aromaticheterocyclic amines such as halogen salts.

Heterocyclic nitrogen moieties may have the following general structure:

where Q₁ may be carbon or nitrogen and Q₂-Q₄ may be nitrogen, oxygen,carbon, or sulfur with the proviso that only one of the Q₂-Q₅ may beoxygen or sulfur at any instance. Preferably, the ring has one to threenitrogen atoms, more preferably one or two nitrogen atoms. Mostpreferably, the ring is an imidazole. The nitrogen which joins the ringto a terminal carbon of formula (XIII) above may have a positive chargewhere a counter anion is X″ where X″ is chloride, bromide, iodide,acetate, sulfate, hydroxyl, boron tetrafluoride or nitrate. The carbonatoms and nitrogen atoms may be substituted or unsubstituted.Substituents on carbon atoms and nitrogen atoms include but are notlimited to, linear or branched, substituted or unsubstituted(C₁-C₁₀)alkyl; hydroxyl; linear or branched alkoxy; linear or branched,substituted or unsubstituted hydroxy(C₁-C₁₀)alkyl; linear or branched,substituted or unsubstituted alkoxy(C₁-C₁₀)alkyl; linear or branched,substituted or unsubstituted carboxy(C₁-C₁₀)alkyl; linear or branched,substituted or unsubstituted amino(C₁-C₁₀)alkyl; substituted orunsubstituted aryl; linear or branched, substituted or unsubstitutedaryl(C₁-C₁₀)alkyl; substituted or unsubstituted sulfonyl; andsubstituted or unsubstituted amine.

Aromatic heterocyclic nitrogen moieties having fused rings may have thefollowing general structure:

where Q₆-Q₁₁ may be carbon, oxygen, nitrogen or sulfur with the provisothat at least one of Q₆ and Q₇ is nitrogen and Q₈-Q₁₁ may be carbon ornitrogen atoms with the proviso that only two of Q₈-Q₁₁ may be nitrogenat the same instance. The carbon and nitrogen atoms of the rings may besubstituted or unsubstituted. Substituents include but are not limitedto, hydroxyl; linear or branched alkoxy; linear or branched, substitutedor unsubstituted hydroxy(C₁-C₁₀)alkyl; linear or branched, substitutedor unsubstituted alkoxy(C₁-C₁₀)alkyl; linear or branched, substituted orunsubstituted carboxy(C₁-C₁₀)alkyl; linear or branched, substituted orunsubstituted amino(C₁-C₁₀)alkyl; substituted or unsubstituted aryl;linear or branched, substituted or unsubstituted aryl(C₁-C₁₀)alkyl;substituted or unsubstituted sulfonyl; and substituted or unsubstitutedamine. Such moieties are derived from compounds which include, but arenot limited to, benzimidazoles, benzotriazoles, benzoxazoles,benzothiazoles, and purines. Preferably, such compounds arebenzimidazoles.

Heterocyclic nitrogen moieties also include those having a generalstructure:

where Q₁₂ may be carbon or nitrogen and Q₁₃-Q₁₇ may be nitrogen, carbonor oxygen with the proviso that at least one of Q₁₂-Q₁₇ is nitrogen andthere are no more than four nitrogen atoms in the ring. The carbon atomsand nitrogen atoms in the ring may be substituted or unsubstituted.Substituent groups may be the same or different and include, but are notlimited to, those substituent groups described for Q₁-Q₁₁, above. WhenQ₁₂ is nitrogen, the nitrogen may have a positive charge where a counteranion is X″ and X″ is as defined above. When oxygen is present in thering, only one of Q₁₃-Q₁₇ is oxygen at any instance. Heterocyclicnitrogen compounds of structure (XVII) may be aromatic or non-aromaticheterocyclic nitrogen compounds.

Preferred aromatic heterocyclic nitrogen containing R′ moieties includethose having the following formulae:

where R₃₂ and R₃₃ are independently hydrogen, (C₁-C₂)alkyl or phenyl;

where R₃₂, R₃₃, R₃₄ and R₃₅ are independently hydrogen, (C₁-C₂)alkyl orphenyl and X″ is as defined above;

where R₃₂ and R₃₃ are as defined above;

where R₃₂, R₃₃, R₃₄ and R₃₅ are as defined above;

where R₃₂, R₃₃, R₃₄ and R₃₅ are as defined above;

where R₃₂, R₃₃, R₃₄, R₃₅ and X⁻ are as defined above; and

where R₃₂, R₃₃, R₃₄, R₃₅ and X⁻ are as defined above;

Preferred moieties also include the following:

where R₃₂ and R₃₃, are as defined above; and

where R₃₂ and R₃₃, are as defined above.

The order of addition of reactants to a reaction vessel may vary,however, preferably, one or more polymers are mixed withdimethylformamide (DMF) at room temperature with dropwise addition ofone or more amine monomers over 0.25 to 1 hour. This is done under anitrogen atmosphere. The mixture is stirred 10-15 hours at roomtemperature. The amounts for each component may vary but, in general,sufficient amounts of each reactant are added to provide a product wherethe molar ratio of polymer to amine monomer ranges from 1:0.05 to 1:2,preferably 1:0.1 to 1:1, based on the molar ratio of the reactants.

The plating compositions and methods which include one or more of thereaction products are useful in providing a substantially level platedmetal layer on a substrate, such as a printed circuit board orsemiconductor chip. Also, the plating compositions and methods areuseful in filling apertures in a substrate with metal. The metaldeposits have good throwing power and good physical reliability inresponse to thermal shock stress tests.

Any substrate upon which metal can be electroplated may be used as asubstrate with the metal plating compositions containing the reactionproducts. Such substrates include, but are not limited to: printedwiring boards, integrated circuits, semiconductor packages, lead framesand interconnects. An integrated circuit substrate may be a wafer usedin a dual damascene manufacturing process. Such substrates typicallycontain a number of features, particularly apertures, having a varietyof sizes. Through-holes in a PCB may have a variety of diameters, suchas from 50 μm to 350 μm in diameter. Such through-holes may vary indepth, such as from 0.8 mm to 10 mm. PCBs may contain blind vias havinga wide variety of sizes, such as up to 200 μm diameter and 150 μm depth,or greater. The plating compositions may also be used to electroplate onplastic materials which include conductive polymers or metal seedlayers.

The metal plating compositions contain a source of metal ions, anelectrolyte, and a leveling agent, where the leveling agent is areaction product of one or more amine monomers and one or more polymerscontaining an imide or anhydride functionality. The metal platingcompositions may contain a source of halide ions, an accelerator and asuppressor. Metals which may be electroplated from the compositionsinclude, but are not limited to, copper, tin and tin/copper alloys.Preferably the metal plated is copper.

Suitable copper ion sources are copper salts and include withoutlimitation: copper sulfate; copper halides such as copper chloride;copper acetate; copper nitrate; copper tetrafluoroborate; copperalkylsulfonates; copper aryl sulfonates; copper sulfamate; copperperchlorate and copper gluconate. Exemplary copper alkane sulfonatesinclude copper (C₁-C₆)alkane sulfonate and more preferably copper(C₁-C₃)alkane sulfonate. Preferred copper alkane sulfonates are coppermethanesulfonate, copper ethanesulfonate and copper propanesulfonate.Exemplary copper arylsulfonates include, without limitation, copperbenzenesulfonate and copper p-toluenesulfonate. Mixtures of copper ionsources may be used. One or more salts of metal ions other than copperions may be added to the present electroplating baths. Typically, thecopper salt is present in an amount sufficient to provide an amount ofcopper metal of 10 to 400 g/L of plating solution.

Suitable tin compounds include, but are not limited to salts, such astin halides, tin sulfates, tin alkane sulfonate such as tin methanesulfonate, tin aryl sulfonate such as tin benzenesulfonate and tinp-toluenesulfonate. The amount of tin compound in these electrolytecompositions is typically an amount that provides a tin content in therange of 5 to 150 g/L. Mixtures of tin compounds may be used in anamount as described above.

The electrolyte useful in the present invention may be alkaline oracidic. Preferably the electrolyte is acidic. Preferably, the pH of theelectrolyte is ≤2. Suitable acidic electrolytes include, but are notlimited to, sulfuric acid, acetic acid, fluoroboric acid, alkanesulfonicacids such as methanesulfonic acid, ethanesulfonic acid, propanesulfonicacid and trifluoromethane sulfonic acid, aryl sulfonic acids such asbenzenesulfonic acid, p-toluenesulfonic acid, sulfamic acid,hydrochloric acid, hydrobromic acid, perchloric acid, nitric acid,chromic acid and phosphoric acid. Mixtures of acids may beadvantageously used in the present metal plating baths. Preferred acidsinclude sulfuric acid, methanesulfonic acid, ethanesulfonic acid,propanesulfonic acid, hydrochloric acid and mixtures thereof. The acidsmay be present in an amount in the range of 1 to 400 g/L. Electrolytesare generally commercially available from a variety of sources and maybe used without further purification.

Such electrolytes may optionally contain a source of halide ions.Typically chloride ions are used. Exemplary chloride ion sources includecopper chloride, tin chloride, sodium chloride, potassium chloride andhydrochloric acid. A wide range of halide ion concentrations may be usedin the present invention. Typically, the halide ion concentration is inthe range of 0 to 100 ppm based on the plating bath. Such halide ionsources are generally commercially available and may be used withoutfurther purification.

The plating compositions typically contain an accelerator. Anyaccelerators (also referred to as brightening agents) are suitable foruse in the present invention. Such accelerators are well-known to thoseskilled in the art. Accelerators include, but are not limited to,N,N-dimethyl-dithiocarbamic acid-(3-sulfopropyl)ester;3-mercapto-propylsulfonic acid-(3-sulfopropyl)ester;3-mercapto-propylsulfonic acid sodium salt; carbonic acid,dithio-O-ethylester-S-ester with 3-mercapto-1-propane sulfonic acidpotassium salt; bis-sulfopropyl disulfide; bis-(sodiumsulfopropyl)-disulfide; 3-(benzothiazolyl-S-thio)propyl sulfonic acidsodium salt; pyridinium propyl sulfobetaine;1-sodium-3-mercaptopropane-1-sulfonate; N,N-dimethyl-dithiocarbamicacid-(3-sulfoethyl)ester; 3-mercapto-ethyl propylsulfonicacid-(3-sulfoethyl)ester; 3-mercapto-ethylsulfonic acid sodium salt;carbonic acid-dithio-O-ethylester-S-ester with 3-mercapto-1-ethanesulfonic acid potassium salt; bis-sulfoethyl disulfide;3-(benzothiazolyl-S-thio)ethyl sulfonic acid sodium salt; pyridiniumethyl sulfobetaine; and 1-sodium-3-mercaptoethane-1-sulfonate.Accelerators may be used in a variety of amounts. In general,accelerators are used in an amount in a range of 0.1 ppm to 1000 ppm.

Any compound capable of suppressing the metal plating rate may be usedas a suppressor in the present electroplating compositions. Suitablesuppressors include, but are not limited to, polypropylene glycolcopolymers and polyethylene glycol copolymers, including ethyleneoxide-propylene oxide (“EO/PO”) copolymers and butyl alcohol-ethyleneoxide-propylene oxide copolymers. Suitable butyl alcohol-ethyleneoxide-propylene oxide copolymers are those having a weight averagemolecular weight of 100 to 100,000, preferably 500 to 10,000. When suchsuppressors are used, they are typically present in an amount in therange of 1 to 10,000 ppm based on the weight of the composition, andmore typically from 5 to 10,000 ppm. The leveling agents of the presentinvention may also possess functionality capable of acting assuppressors.

In general, the reaction products have a number average molecular weight(Mn) of 200 to 100,000, typically from 300 to 50,000, preferably from500 to 30,000, although reaction products having other Mn values may beused. Such reaction products may have a weight average molecular weight(Mw) value in the range of 1000 to 50,000, typically from 5000 to30,000, although other Mw values may be used.

The amount of the reaction product (leveling agent) used in the metalelectroplating compositions depends upon the particular leveling agentsselected, the concentration of the metal ions in the electroplatingcomposition, the particular electrolyte used, the concentration of theelectrolyte and the current density applied. In general, the totalamount of the leveling agent in the electroplating composition rangesfrom 0.01 ppm to 500 ppm, preferably from 0.1 ppm to 250 ppm, mostpreferably from 0.5 ppm to 100 ppm, based on the total weight of theplating composition, although greater or lesser amounts may be used.

The electroplating compositions may be prepared by combining thecomponents in any order. It is preferred that the inorganic componentssuch as source of metal ions, water, electrolyte and optional halide ionsource are first added to the bath vessel, followed by the organiccomponents such as leveling agent, accelerator, suppressor, and anyother organic component.

The electroplating compositions may optionally contain at least oneadditional leveling agent. Such additional leveling agents may beanother leveling agent of the present invention, or alternatively, maybe any conventional leveling agent. Suitable conventional levelingagents that can be used in combination with the present leveling agentsinclude, without limitations, those disclosed in U.S. Pat. No. 6,610,192to Step et al., U.S. Pat. No. 7,128,822 to Wang et al., U.S. Pat. No.7,374,652 to Hayashi et al. and U.S. Pat. No. 6,800,188 to Hagiwara etal. Such combination of leveling agents may be used to tailor thecharacteristics of the plating bath, including leveling ability andthrowing power.

Typically, the plating compositions may be used at any temperature from10 to 65° C. or higher. Preferably, the temperature of the platingcomposition is from 10 to 35° C. and more preferably from 15 to 30° C.

In general, the metal electroplating compositions are agitated duringuse. Any suitable agitation method may be used and such methods arewell-known in the art. Suitable agitation methods include, but are notlimited to: air sparging, work piece agitation, and impingement.

Typically, a substrate is electroplated by contacting the substrate withthe plating composition. The substrate typically functions as thecathode. The plating composition contains an anode, which may be solubleor insoluble. Potential is typically applied to the electrodes.Sufficient current density is applied and plating performed for a periodof time sufficient to deposit a metal layer having a desired thicknesson the substrate as well as to fill blind vias, trenches andthrough-holes, or to conformally plate through-holes. Current densitiesmay range from 0.05 to 10 A/dm², although higher and lower currentdensities may be used. The specific current density depends in part uponthe substrate to be plated, the composition of the plating bath, and thedesired surface metal thickness. Such current density choice is withinthe abilities of those skilled in the art.

An advantage of the present invention is that substantially level metaldeposits are obtained on a PCB. Through-holes, blind vias orcombinations thereof in the PCB are substantially filled orthrough-holes are conformally plated with desirable throwing power. Afurther advantage of the present invention is that a wide range ofapertures and aperture sizes may be filled or conformally plated withdesirable throwing power.

Throwing power is defined as the ratio of the average thickness of themetal plated in the center of a through-hole compared to the averagethickness of the metal plated at the surface of the PCB sample and isreported as a percentage. The higher the throwing power, the better theplating composition is able to conformally plate the through-hole.

The compounds provide metal layers having a substantially level surfaceacross a substrate, even on substrates having small features and onsubstrates having a variety of feature sizes. The plating methodseffectively deposit metals in through-holes such that the metal platingcompositions have good throwing power.

While the methods of the present invention have been generally describedwith reference to printed circuit board manufacture, it is appreciatedthat the present invention may be useful in any electrolytic processwhere an essentially level or planar metal deposit and filled orconformally plated apertures are desired. Such processes include, butare not limited to, semiconductor packaging and interconnectmanufacture.

The following examples are intended to further illustrate the inventionbut are not intended to limit its scope.

Example 1

Polysuccimide (2.4 g, 24.7 mmoles) and 20 mL dimethylformamide (DMF)were added to a three necked flask round bottomed flask. Aminopropylimidazole (3.24 g, 25.9 mmoles) in 5 mL DMF was added dropwise over aperiod of 0.5 hours with stirring under a nitrogen atmosphere. Themixture was stirred at room temperature for 12 hours. Then the solventwas evaporated and the product was washed with acetone to remove residueof DMF and any unreacted aminopropyl imidazole. The molecular weights ofthe unpurified product were determined to be Mn=4594 and Mw=9206.

Three aqueous acid copper electroplating baths were prepared as shown inTable 1 below. The reaction product was included in the baths withoutpurification.

TABLE 1 COMPNENT BATH 1 BATH 2 BATH 3 Purified copper sulfate 73 g/L 73g/L 73 g/L pentahydrate Sulfuric acid 235 g/L 235 g/L 235 g/L Chlorideions as hydrogen 60 ppm 60 ppm 60 ppm chloride Reaction product of 0 ppm10 ppm 20 ppm polysuccinamide and aminopropyl imidazole (leveler)bis(sodium- 3 ppm 3 ppm 3 ppm sulfopropyl)disulfide EO/PO copolymer witha 1.5 g/L 1.5 g/L 1.5 g/L molecular weight of <5000 and terminalhydroxyl groups

Test panels 3.2 mm thick with average through-hole diameters of 300 μmwere immersed in the three aqueous acid copper electroplating baths.Copper plating was done for 80 minutes at 25° C. The current density was2.16 ASD. The copper plated samples were analyzed to determine thethrowing power (“TP”) of the plating bath, and percent crackingaccording to the following methods.

Throwing power was calculated by determining the ratio of the averagethickness of the metal plated in the center of a through-hole comparedto the average thickness of the metal plated at the surface of the testpanel. The throwing power is reported in Table 2 as a percentage.

The percent cracking was determined according to the industry standardprocedure, IPC-TM-650-2.6.8. Thermal Stress, Plated-Through Holes,published by IPC (Northbrook, Ill., USA), dated May, 2004, revision E.

TABLE 2 Leveler Hole thickness Surface thickness Cracking (ppm) (μm)(μm) TP % ratio 0 12.6 27.5 45.8 0 10 16.2 25.7 63.0 0 20 17.9 26.6 67.30

The average surface thickness of the copper plated on the panels wassubstantially the same for each sample. Through-hole thickness wasimproved in the two baths which included the leveler. Improved throwingpower was also observed in the copper plating baths which included thereaction product over the bath which excluded it. All of the samplestested had good cracking results. The lower the percentage of cracking,the better was the plating performance. Preferably, cracking was ≤10%.

Example 2

The copper electroplating process described above was repeated using thesame reaction product in each bath but the amount varied. In addition,the amount of brightener added to the copper baths was either 1 ppm or 3ppm as shown in the table below. The electroplating conditions were thesame as in Example 1 as well as the type of substrates plated. Theresults are shown in Table 3.

TABLE 3 Hole Surface thick- thick- Ap Sam- Leveler Brightener ness nessCracking pear- ple (ppm (ppm) (μm) (μm) TP % % ance 1 1 1 10.1 25.3 4.00 bright 2 2 1 14.3 26.3 54.4 0 bright 3 5 1 14.8 25.33 58.0 0 bright 410 1 14.55 26.3 55.3 0 bright 5 20 1 13.4 26.8 50.0 0 bright 6 5 3 15.827.1 58.3 0 bright 7 10 3 16.2 25.7 63.0 0 bright 8 20 3 17.9 26.6 67.30 bright 9 50 3 15.8 27.2 58.1 0 bright

All of the deposits were bright and smooth in appearance. Throwing powerwas good overall with the best results achieved in samples 6 and 7 atleveler concentrations of 10 ppm and 20 ppm. No cracking was observed.This was consistent with the results in Example 1 above.

Example 3

To a three necked round-bottom flask 25 mmoles of polysuccimide and 20mL dimethylformamide (DMF) were added. Then 26 mmoles of an amine havingformula:

in 5 mL DMF was added dropwise over a period of 0.5 hours with stirringunder a nitrogen atmosphere. The mixture was stirred at room temperaturefor 12 hours. Then the solvent was evaporated and the product was washedwith acetone to remove any residue.

Three aqueous acid copper electroplating baths were prepared having theformulation disclosed in Table 1 of Example 1 except the amount ofbrightener was 1 ppm. The reaction product was included in the bathswithout purification. The amount of reaction product or leveler was usedin amounts as shown in Table 4 below.

TABLE 4 Hole Surface thick- thick- Ap Sam- Leveler Brightener ness nessCracking pear- ple (ppm (ppm) (μm) (μm) TP % % ance 1 5 1 8.95 25.6 35 0bright 2 10 1 13.8 26.4 52.3 0 bright 3 20 1 12.5 23.6 53 50 matte

Acceptable throwing power values were obtained for samples 2 and 3;however, sample 3 had a high cracking ratio and the deposit was matte.

Example 4

To a three necked round-bottom flask 25 mmoles of polysuccimide and 20mL dimethylformamide (DMF) were added. 25 mmoles of an amine havingformula:

in 5 mL DMF was then added dropwise over a period of 0.5 hours withstirring under a nitrogen atmosphere. The mixture was stirred at roomtemperature for 12 hours. Then the solvent was evaporated and theproduct was washed with acetone to remove any residue.

An aqueous acid copper electroplating bath was prepared having theformulation disclosed in Table 1 of Example 1 except the amount ofbrightener was 1 ppm. The reaction product was included in the bathswithout purification. The amount of reaction product or leveler was usedin the amount as shown in Table 5 below. Plating was done as describedin Example 1 above using the same type of panel.

TABLE 5 Hole Surface thick- thick- Ap Sam- Leveler Brightener ness nessCracking pear- ple (ppm (ppm) (μm) (μm) TP % % ance 1 50 1 13.35 27.548.5 0 bright

The copper deposit was bright and the throwing power was an acceptablevalue. No cracking was observed.

Example 5

To a three necked round-bottom flask 25 mmoles of polysuccimide and 20mL dimethylformamide (DMF) were added. 25 mmoles of an amine havingformula:

in 5 mL DMF was then added dropwise over a period of 0.5 hours withstirring under a nitrogen atmosphere. The mixture was stirred at roomtemperature for 12 hours. Then the solvent was evaporated and theproduct was washed with acetone to remove any residue.

Three aqueous acid copper electroplating baths were prepared having theformulation disclosed in Table 1 of Example 1 except the amount ofbrightener was 1 ppm. The reaction product was included in the bathswithout purification. The amount of reaction product or leveler was usedin the amount as shown in Table 6 below. Plating was done as describedin Example 1 above using the same type of panel.

TABLE 6 Hole Surface thick- thick- Ap Sam- Leveler Brightener ness nessCracking pear- ple (ppm (ppm) (μm) (μm) TP % % ance 1 5 1 16.5 27.2 60.70 bright 2 10 1 14.5 26.5 55 0 bright 3 20 1 14.16 26.7 53 0 bright

All of the samples showed good throwing power and all have brightdeposits. No cracking was observed on any of the deposits.

Example 6

To a three necked round-bottom flask 25 mmoles of polysuccimide and 20mL dimethylformamide (DMF) were added. 25 mmoles of an amine havingformula:

in 5 mL DMF was then added dropwise over a period of 0.5 hours withstirring under a nitrogen atmosphere. The mixture was stirred at roomtemperature for 12 hours. Then the solvent was evaporated and theproduct was washed with acetone to remove any residue.

Six aqueous acid copper electroplating baths were prepared having theformulation disclosed in Table 1 of Example 1. The amount of brightenerin the baths was either 1 ppm or 3 ppm. The reaction product wasincluded in the baths without purification. The amount of reactionproduct or leveler was used in the amount as shown in Table 7 below.Plating was done as described in Example 1 above using the same type ofpanels.

TABLE 7 Hole Surface thick- thick- Ap Sam- Leveler Brightener ness nessCracking pear- ple (ppm (ppm) (μm) (μm) TP % % ance 1 1 1 14.55 26.954.1 80 bright 2 5 1 16.5 25.2 65.4 100 matte 3 5 3 17.0 27.1 62.7 0bright 4 10 3 18.3 25.6 71.5 80 bright 5 20 3 18.4 27.7 66.4 0 bright 650 3 18.3 28.6 64.0 0 bright

Overall throwing power was very good; however, cracking was a problem inhalf of the samples analyzed. Deposits were bright over all.

Example 7

To a three necked round-bottom flask 25 mmoles of polysuccimide and 20mL dimethylformamide (DMF) were added. 25 mmoles of an amine havingformula:

in 5 mL DMF was then added dropwise over a period of 0.5 hours withstirring under a nitrogen atmosphere. The mixture was stirred at roomtemperature for 12 hours. Then the solvent was evaporated and theproduct was washed with acetone to remove any residue.

Six aqueous acid copper electroplating baths were prepared having theformulation disclosed in Table 1 of Example 1. The amount of brightenerin the baths was 1 ppm, 2 ppm or 3 ppm. The reaction product wasincluded in the baths without purification. The amount of reactionproduct or leveler was used in the amount as shown in Table 8 below.Plating was done as described in Example 1 above using the same type ofpanels.

TABLE 8 Hole Surface thick- thick- Ap Sam- Leveler Brightener ness nessCracking pear- ple (ppm (ppm) (μm) (μm) TP % % ance 1 5 1 14.9 26.6 56100 bright 2 10 1 14.3 26.1 54.8 100 matte 3 5 3 16.2 24.7 65.6 100bright 4 10 3 15.6 24 62.5 100 bright 5 1 1 16.3 25.4 64.2 100 bright 61 2 17 27.5 61.8 20 bright

All of the samples had good throwing power, however, cracking wasprevalent.

Example 8

To a three necked round-bottom flask 25 mmoles of polysuccimide and 20mL dimethylformamide (DMF) were added to a three necked flask. 25 mmolesof an amine having formula:

1-methyl-3-(2-aminopropyl)imidazolium hydrobromide in 5 mL DMF was addeddropwise over a period of 0.5 hours with stirring under a nitrogenatmosphere. The mixture was stirred at room temperature for 12 hours.Then the solvent was evaporated and the product was washed with acetoneto remove any residue.

Three aqueous acid copper electroplating baths were prepared having theformulation disclosed in Table 1 of Example 1. The amount of brightenerin the baths was 1 ppm or 3 ppm. The reaction product was included inthe baths without purification. The amount of reaction product orleveler was used in the amount as shown in Table 9 below. Plating wasdone as described in Example 1 above using the same type of panels.

TABLE 9 Hole Surface thick- thick- Ap Sam- Leveler Brightener ness nessCracking pear- ple (ppm (ppm) (μm) (μm) TP % % ance 1 1 3 15.9 29 54.8 0bright 2 1 1 17.5 27 64.8 60 bright 3 0.5 1 16.7 26.9 62.1 0 bright

Throwing power was good for all of the baths. Significant cracking wasobserved in only sample 2. No cracking was observed in samples 1 and 3.All deposits were bright.

Example 9

To a three necked round-bottom 25 mmoles of polysuccimide and 20 mLdimethylformamide (DMF) were added. 25 mmoles of an amine havingformula:

(2-aminopropyl)-4-methyl pyridinium hydrobromide in 5 mL DMF was thenadded dropwise over a period of 0.5 hours with stirring under a nitrogenatmosphere. The mixture was stirred at room temperature for 12 hours.Then the solvent was evaporated and the product was washed with acetoneto remove any residue.

Three aqueous acid copper electroplating baths were prepared having theformulation disclosed in Table 1 of Example 1. The amount of brightenerin the baths was 1 ppm or 3 ppm. The reaction product was included inthe baths without purification. The amount of reaction product orleveler was used in the amount as shown in Table 10 below. Plating wasdone as described in Example 1 above using the same type of panels.

TABLE 10 Hole Surface thick- thick- Ap Sam- Leveler Brightener ness nessCracking pear- ple (ppm (ppm) (μm) (μm) TP % % ance 1 1 1 12.5 26.6 47100 bright 2 1 3 18 27 66.7 0 bright 3 5 3 14 26.6 53.8 100 brightThrowing power was good for samples 2 and 3. However, significantcracking was observed in samples 1 and 3. All deposits were bright.

Example 10

To a three necked round-bottom flask 25 mmoles of polysuccimide and 20mL dimethylformamide (DMF) were added. 25 mmoles of an amine havingformula:

N-(3-aminobutyl) guanidine in 5 mL DMF was then added dropwise over aperiod of 0.5 hours with stirring under a nitrogen atmosphere. Themixture was stirred at room temperature for 12 hours. Then the solventwas evaporated and the product was washed with acetone to remove anyresidue.

Three aqueous acid copper electroplating baths were prepared having theformulation disclosed in Table 1 of Example 1. The amount of brightenerin the baths was 1 ppm, 2 ppm or 3 ppm. The reaction product wasincluded in the baths without purification. The amount of reactionproduct or leveler was used in the amount as shown in Table 11 below.Plating was done as described in Example 1 above using the same type ofpanels.

TABLE 11 Hole Surface thick- thick- Ap Sam- Leveler Brightener ness nessCracking pear- ple (ppm (ppm) (μm) (μm) TP % % ance 1 0.5 1 13.3 24.554.3 30 matte 2 0.5 2 16.8 26.3 63.8 72.5 matte 3 0.5 3 15.8 23.7 66.722.5 matte 4 0.25 3 12.5 27.3 45.8 32.5 matteWith the exception of sample 4, the throwing power was good, however,cracking was significant. Deposit appearances were matte.

What is claimed is:
 1. A reaction product of one or more amine monomersand one or more polymers, the one or more polymers have the formula:

where R₁ and R₂ can be the same or different and comprise hydrogen,linear or branched (C₁-C₅)alkyl, hydroxyl, linear or branched(C₁-C₅)hydroxyalkyl, linear or branched (C₁-C₅)carboxyalkyl, linear orbranched (C₁-C₅)alkoxy, linear or branched (C₁-C₅)haloalkyl, aryl,linear or branched arylalkyl, or linear or branched, aminoalkyl and m isan integer of 2-8.
 2. The reaction product of claim 1, wherein the oneor more amine monomers are chosen from compounds having formula:

where R₂₉ is hydrogen or linear or branched (C₁-C₅)alkyl, r is aninteger of 0 to 8 with the proviso that when r is 0, R′ is joined to thenitrogen atom by a covalent bond and R′ is a linear or branched nitrogencontaining moiety, aromatic or non-aromatic heterocyclic groups.